It is common in the cleaning of a gas e.g. before it is released into the atmosphere or used to recover valuable constituents or to participate in chemical reactions, and especially flue gases of various combustion processes, metallurgical waste gases and gases produced by other industrial processes which may contain soluble noxious and/or toxic substances (including sulfur and nitrogen compounds) as well as dust and particulates, to subject the gas to a wet cleaning in which it is sprayed with scrubbing liquor as the gas flows in a line. Thereafter the resulting gas-liquid mixture is passed through a cyclone separator and purified gas and contaminated scrubbing liquor are separately withdrawn from said separator. During their wet purification, the gases may be cooled and/or chemically treated.
Processes and apparatuses of this kind are known from German Patent 960,452, German Patent Publication 1,300,093, and International Application WO 88/03050.
In these cases the lines which are traversed by the gas to be purified as it flows into the cyclone separator are provided with means for spraying scrubbing liquor. However in these systems there is no optimum contact between the gas and liquid.